Gas turbine driven plant for supplying compressed air



5, 1958 w. TRAUPEL 2,845,776

GAS TURBINE DRIVEN PLANT FOR SUPPLYING COMPRESSED AIR Original FiledMarch 12, I952 4 Sheets-Sheet 1 INVENTOR WALTER TRAUPEL 2am $421M,mwzam/g ATTORNEY5 Aug. 5, 1958 w. TRAUPEL 2,345,776

GAS TURBINE DRIVEN PLANT FOR SUPPLYING COMPRESSED AIR Original FiledMarch 12, 1952 4 Sheets-Sheet 2 INVENTOR WALTER TRAUPEL ATTORNE BY I 25wm MfiWm Ma 7 4+- Aug. 5, 1958 w. TRAUPEL 2,845,776

GAS TURBINE DRIVEN PLANT FOR 'SUPPLYING COMPRESSED AIR Original FiledMarch 12, 1952 4 Shets-Sheet 3 I at INVENTOR W41 75/? 77934 U/ fLATTORNEYS v Aug. 5, 1958 'w. TRAUPEL 2,845,776

GAS TURBINE DRIVEN PLANT FOR SUPPLYINC COMPRESSED AIR Original FiledMarch 12, 1952 4 Sheets-Sheet 4 Fig. 4

INVENTOR WAfiLTER TRAUPEL BY M M 7 ,2, M A? ATTOR EYS 2,845,776 latentedAug. 5,. 1 958 GAS TURBINE DRIVEN PLANT FOR SUPPLYING COMPRESSED AIRWalter Traupel, Winterthur, Switzerland, assignor to Sulzer Frres, SocitAnonyme, Winterthur, Switzerland Continuation of abandoned applicationsSerial No. 276,179, March 12, 1952, and Serial N 0. 282,103, April 14,61952. This application July 30, 1954, Serial No. 44 ,916

9 Claims. (Cl. 60--39.07)

This invention relates to a gas turbine driven installation for theproduction of a supply of compressed air. The installation has an outputcompressor (hereinafter for clarity called a blower) which is driven bya gas turbine plan having its own separate compressor (hereinafter forclarity called the main compressor) which in turn compresses the turbineworking medium, in the example shown, the combustion air supplied tothecombustion chamber. In closed or semi-closed cycle gas turbineplants, the fluid compressed in the main compressor might be not at allor only partly used as combustion air. This application is acontinuation of my applications SerialNo. 276,179 and Serial No. 282,103filed March 12, 1952 and April 14, 1952 respectively, now abandoned.

Recently, attempts have been made to accelerate combustion processes ingeneral, and in particular, in blast furnaces, by increasing thepressure of the combustion air supplied by blowers. Pressures soincreased are in the range of pressures which are also suffic'ient forthe operation of gas turbine plants. The use of a gas turbine as a primemover plant makes possible a particularly favorable regulation of theblower. According to this invention, the delivery side of the blower isconnected by a regulating pipe to a part of the gas turbine plantcontaining the plant working medium wher'e'the pressure of the workingmedium is less than thatof the air on the discharge side of the blower.Means are provided in the regulating pipe for adjusting flow from theblower to the point in the working medium path where the pressure isless than that of the delivery side of the blower. Air will then flowbecause of the pressure difierential from the blower to the maincompressor under all conditions of normal plant operation if theregulating means in the regulating pipe are left open. If there is asudden drop in the demand for air, the surplus can be diverted withoutloss to the gas turbine plantv proper and the energy therein containedcan be utilized instead of wasted.

The blower may, in addition, be connected through adischarge pipe with apoint outside the plant, which has a lower pressure, at least duringnormal operations, than prevails at the entrance into this dischargepipe. An ele-' ment for the adjustment of its through-flow cross-sectionmay also be disposed in the discharge pipe. The gas turbine installationmay also be coupled additionally with an electric machine, which isconnected to an electric power distribution network. A cooler and, ifnecessary, a non-return valve can be arranged in the regulating pipe,which non-return Valve prevents an outflow of working medium from thecompressor of the gas turbine installation. In the delivery pipe of theblower an element for the adjustment of the through-flow crosssectionmay be disposed. In certain cases the blower may be driven by the gasturbine installation through speed multiplication gearing. The electricmachine may be driven by the gas turbine installation through a frictionclutch disengageable at will.

The invention is explained in more detail below, in

connection with three examples of compressed air plants diagrammaticallyillustrated in the accompanying drawings, in which like numerals denotelike parts and in which:

Fig. 1 shows a simple plant;

Fig. 2 discloses a more complicated plant having a number of additionsto the plant shown in Fig. 1;

Fig. 3 shows a plant having a main compressor different from that shownin Figs. 1 and 2; and

Fig. 4 shows a plant wherein a regulating pipe runs from the deliveryside of the blower to the combustion chamber of the gas turbineinstallation.

In the plants according to both Figs. 1 and 2, there is a blower 1,which is driven by a gas turbine installation. The gas turbineinstallation in both comprises basically a compressor 2, a combustionchamber 3, a gas turbine 4 and a recuperator 5. A gas, for example blastfurnace gas, is used in the installations illustrated as fuel for thecombustion chamber 3 and is supplied through a compressor 6 to a burner7. The compressor 6 is driven by the gas turbine 4 through a speedmultiplying gear 8.

The compressor 2 of the gas turbine installation sucks combustion airthrough an intake pipe 9, compresses the same and conveys it through apipe 10 into the recuperator 5. Here it is preheated by exhaust gas fromthe gas turbine 4 and then led through a pipe 11 into the combustionchamber 3. The fuel gas introduced through the burner 7 burns in the airdelivered from compressor 2, producing a heated gaseous mixture ofcombustion products and excess air gases. These heated and compressedgases then pass through a pipe 12 into the turbine 4 and, after beingexpanded therein to produce power, pass through a pipe 13 into therecuperator 5. After giving off a part of their heat in recuperator 5 tothe freshly compressed air, these gases flow through a pipe 14 away fromthe gas turbine installation.

For regulating the output of the gas turbine installation, the pipe 15,through which fuel gas is supplied to the burner 7, has a by-pass pipe16, through which, according to the adjustment of the flow regulatingelement 17, a part of the compressed fuel gas can be led back to thecompressor 6. In orderto avoid an inadmissible heating in this case, acooler 18 is arranged in by-pass pipe 16, which cools returned gas toabout the temperature of the fuel being supplied through pipe '19. Inpipe 15 there is also a flow regulating element 20 by which regulationof the gas turbine installation can be still further improved.

The described gas turbine installation is coupled-through a speedmultiplying gear 21 withthe blower 1. This production compressor sucksin air, e. g. from the open air, through a pipe 22 and conveys itthrough the pipe 23 to a point of use not shown, for example ascombustion air into a blast furnace.

According to the invention .the blower is connected through a regulatingpipe 24 with an intermediate stage 25 of the compressor 2 of the gasturbine installation. This intermediate stage has, during normaloperations, a lower pressure than that prevailing at the entrance intothe regulating pipe 24. Furthermore an element 26 is disposed inthe'regulating pipe 24, which serves for the adjustment of thethrough-flow cross-section. In addition there is connected to theregulating pipe 24 a discharge pipe 27 with a flow regulating element28, through which compressed air can be discharged outside the plant toa point where a lower pressure prevails than in the pipe 2'7.

The gas turbine installation is, in addition, coupled through gearing 29with an electric machine 38, which in its turn is connected to anelectric power supply network 31.

By adjustment ofthe cross-section of the regulating element 26 theamount of air conveyed through the pipe 23 to the point of use can beeasily determined within desired limits. The more regulating element 26is closed, the greater portion of the air delivered by the blower issupplied to the point of use. Conversely, the more the cross-section ofthe regulating element 26 is made larger, the smaller amount of airflows to the point of use. If the regulating element 26 is completelyopen, the delivery pressure of the blower and the pressure of theintermediate stage 25 of the compressor 2 of the gas turbineinstallation are practically equal. Then the greatest possible amount ofair flows from the blower over into the compressor 2. If one wishes todecrease still more the amount of air supplied through pipe 23 to thepoint of use, valve 28 in discharge pipe 27 is opened, so that a part ofthe air is discharged outside the plant. In this manner a practicallyloss-free regulation of the amount of production air delivered by theplant can be attained over the normal range of operations. By this meansthe efiiciency of operation is improved.

A further simplification of the regulation is produced by the electricmachine 30. This machine runs synchronously with the network 31. If thegas turbine installation generates more power than is required by theblower, the surplus is supplied to the network 31 in the form ofelectric energy. Without any regulating adjustments the supply ofelectric energy, surplus energy, is always adapted to the differencebetween gas turbine output and thepower required by the blower. If theoutput of the gas turbine installation is smaller than the powerdemanded by the blower, the electric machine 39 operates as a motor andsupplements the lack of power. In most cases, however, it will bedesirable to so proportion the plant that in any foreseeable state ofoperation power will be supplied to the network by the electric machine30. If the electric machine 30 is mechanically disconnected from it, thegas turbine 4 can be operated at a greater or lesser speed independentlyof the frequency of the network 31.

As shown in Fig. 2, a cooler 32 can be disposed in the regulating pipe24, 'by which the eliiciency of the gas turbine installation can bestill further improved. In addition, it is desirable to arrange a checkvalve 33 in pipe 24 in order to prevent a return flow of air fromcompressor 2 to the discharge pipe 27.

The fuel gas compressor 6 can also be equipped with a recuperation motor34 disposed in the bypass pipe 16. By these measures the efliciency ofthe delivery of fuel gas can be still somewhat improved.

Finally, a hydraulic coupling 35 can be used between the gas turbine 4and the electric machine 30, so that the operation of the gas turbineinstallation can be adjusted independently of the frequency of thenetwork. The coupling 35 is constructed as hydraulic gear so that thespeed and thus the transmitted moment can be altered suitably.

In the place of such hydraulic gear, a suitable equivalent mechanicalgear could also be used.

A flow regulating element 36 may also be advantageously disposed in thepipe 23 supplying air from the blower to point of use.

Of course, it will be readily understood that the gas turbineinstallation can be operated on other fuel, for example on coal or oil.In using coal, this would preferably be in dust form.

In Fig. 3, a slightly different embodiment of the invention is shownthan that disclosed in Fig. 1. Here the regulating pipe 24 is connectedto the discharge side of the main compressor 2 which is so dimensionedthat it generates a lower pressure than the blower 1 under normal plantconditions. It is also possible when using a main compressor dimensionedaccording to this embodiment of the invention to have the regulatingpipe 24 connect to any point in the path of the fiow of the workingmedium between the recuperator 5 and the gas burner or even to theburner itself, as seen in Fig. 4.

Iclaim:

1. In an installation for producing compressed air for external use ofthe type in which a blower for the product air is driven by a gasturbine power plant which includes a separate main compressor tocompress air from the atmosphere for intra-power plant use, a regulatingpipe, and a pipe running from the discharge side of said blower to thepoint of external use, the improvement characterized in that the outletof the blower is connected by said regulating pipe to a point in thepath of the at least partially compressed working medium of said gasturbine power plant which has a lower pressure than the deliverypressure of said blower, means in said regulating pipe for adjustingflow of compressed air from said blower to said point in the path ofsaid working medium and an electric machine connected to an electricalpower supply network in driving and driven coupling to the gas turbinepower plant.

2. An installation according to claim 1 wherein the point in the path ofthe working medium having less pressure than the delivery side of saidblower is at an intermediate stage of said main compressor and whereinsaid regulating pipe leads to said intermediate stage.

3. An installation according to claim 1, wherein the pressure of theworking medium on the delivery side of the main compressor is less thanthe pressure of the compressed air on the delivery side of the blowerand wherein said regulating pipe intersects the path of the workingmedium downstream of said main compressor.

4. An installation according to claim 1 wherein the delivery side of theblower is connected to a conduit having therein a regulating means forregulating flow to a point outside of said installation, said conduitbeing in addition to said regulating pipe and said pipe running to thepoint of external use.

5. An installation according to claim 1 wherein there is a coolermounted in said regulating pipe.

6. An installation according to claim 1 wherein said regulating pipe isprovided with a check valve to prevent flow of the working medium fromsaid main compressor through said regulating pipe.

7. An installation according to claim 1 wherein said blower ismechanically coupled with the turbine of said turbine power plant by aspeed increasing gear train.

8. An installation according to claim 7 wherein the coupling of theelectric machine is capable of engaging or disengaging.

9. An installation according to claim 7 wherein said regulating pipe isconnected with a combustion chamber of the gas turbine plant.

References Cited in the file of this patent UNITED STATES PATENTS

